Theor. relations for the chronoamperometric and chronocoulometric response to a double-potential step for a simple electrode reaction at an ultramicrodisk electrode are presented. The experimental investigation employs the oxidation of K4Fe(CN)6 in the presence of KCl at Pt ultramicrodisk electrode with radius 10 mm, and the general-purpose microcomputer-based instrumentation used in this work was made in the authors' laboratory The experimental results agreed with the theory.

Key words: POTASSIUM CHLORIDE, MICROELECTRODE, CHRONOCOULOMETRY